Hydraulic clutch



G. H. WALKER Dec. 9, 1930.

HYDRAULIC'` CLUTCH Filed Jan. 9, 1929 3 Sheets-Sheet l l Q W I v Dec. 9, 1930. G, H, WALKER 1,784,212

HYDRAULIC CLUTCH Filed Jan. 9, 1929 s sheets-she`et 2 Eg' v INVENTOR.

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lDec. 9, 1930. G, H- WALKER I 1,784,212

` HYDRAULIC CLUTCH Filed Jan. 9. 1929 3 sheetslsheet 5 l lnmfeiiy Dee. 9, 1930 UNITED STATES PATENT OFFICE GEORGE HENRY WALKER, CF WORCESTER, ENGLAND, ASSIGNOR TO HEEN LIMITED, 0F WORCESTER, ENGLAND HYDRAULIC CLUTCH Application led January 9, 1929, Serial No. 331,358, and in Great Britain January 20, 1928.

rihis invention relates to improvements in hydraulic clutches of the type in which power is transferred from the driving to the drivenl element by hydraulic reaction without the aid of solid friction.

In this type of clutch, power can only be transmitted by virtue of relative motion between driving'and driven elements i. e. slip is necessary. The amount of slip can be rendered very small by suitably proportioning the'clutch, but even so, slight heating of the working liquid due to slip is unavoidable. In order to limit the temperature rise of the liquid, arrangements are usually made to recirculate the liquid through cooling devices or to sup-ply fresh cool liquid to the working compartment of the clutch. Hitherto the passages for entry of the cool liquid into the clutch have communicated from the exterior with a part of the clutch where, due to the effects of centrifugal force and f hydraulic transmission of power, thepressure of the liquid is high. This has necessitated the use of a liquid-circulating pump developing a comparatively high pressure, to overcome the resistance to entry of the liquid.

According to the present invention the clutch is formed of two members, a' rotor and an outer casing. both of which are adapted to rotate and which are formed with cup's or pockets in which the liquid circulates, passages being formed in the vanes separating adjacent cups in the casingthrough which the lfresh cooled liquid enters and is conveyed to the centre of the cups or pockets where the pressure is at a minimuml owing to the eddies or vortices which are set up therein, the heated liquid being discharged through outlet passages at or near the periphery of the casing.

In carrying out the invention one or more l rotors vare .mounted upon a shaft transmitting the drive from the clutch and revolving within a casing whichl is coupled by shafting or otherwise geared to the machine or apparatus supplying the power. The casing itself is free to revolve upon bearings which may be either external to the casing or may be interposed between the caslng and rotor shaft. The casing is capable of being filled with liquid such as oil, water or in exceptional instances with a heavy liquid such as mercury, and will then transmit power by hydraulic interaction between rotor and casing; or it may be emptied of liquid, when the power transmitted will be nil; or it may be partially emptied, allowing considerable slip to take place between driving and driven shafting.

In order to avoid theise of a high pressure liquid-circulating pumpand the consequent lossw of eiiiciency, the .rotor or rotors and casing employed may be similar to those of the Froude hydraulic dynamometer, as described in British Patents Nos. 24,949of 1910 (Fi s. 2 and 3), 163733016 1913, and

243,837 o 1924 (Fig. 2).

The invention will be described with reference to the accompanying drawings y Fig. l is a longitudlnal section through an hydraulic clutch in which the rotor and casing are similar to. those of the .Froude hydraulic dynamometer referred to above. Y

Fig. 2 is a section of a quick acting outlet valve for rapidly discharging the liquid from the high pressure zone of the casing.

Fig. 3 is a detail view of the outlet passages.

Fig. 4 is a side view f the cups in the casiIl B.

gFig. 5 is a section on line V5--5 Fig. 4.

In the form of hydraulic clutch shown in the drawings the driving element is formed by the casing B which is mounted on a shaft C, the free end of which is fitted with'a coupling (not shown) or other lsuitable means for connecting the shaftl with the prime mover.` -As shown the casing -B is bolted to or otherwise ailixed thereto.

The rotor E is mounted on a second shaft F extending in the Yopposite direction to the shaft C and fitted with a coupling (not shown) or other suitable means Vfor connecting the shaft with the driven machinery. The rotor E is shown keyed on to the shaft F but it may be aixed thereto in any other convenient manner. The inner end of the shaft y C is -hollow and the inner end of the shaft F projects into this hollow a lining f being provided between them to foiin a bearing surface for the end of the shaft F.

The part of the casing B which extends- .beyond the inner end of the shaft C is bolted to-ar flange c1 on a sleeve C1 surrounding the 'shaft F, a bearing surface f1 being arranged between the shaft F and sleeve C1 to allow of their freely rotating in relation to one another. y Cups or pockets @are formed in the rotor E and similar cups or pockets b are formed in the casing B and the liquid circulates in these kets under the influence of the rotation o the rotor E creating eddies or vortices g5 which resist relative motion between the casing B and the rotor E and tend to drive the rotor E in the same direction of rotation as the casing B. Adjacent cups in the rotor E andalso in the casing '4B are separated by so vanes efz and b" respectively, passages b1- being formed in the vanes b' of the casing B for the ent of the liquid into the cups. The cool liquid enters Athe lapparatus through a gland- H the non-rotating part of which is provided 35 with a port or ports H1. The port or ports H1 are under' the control of a valve not shown in the drawing by which liquid may be admitted to or shut off from the clutch.

The liquid' from lthe 'gland H ythrough the ring of apertures c2 in the sleeve C1 to the annular s ace between the sleeve C1 and the .shaft FP an thence through the ring of apertures c3 in the sleeve C1 to the passages 1 in the vanes of the casing B.

The passages b1 deliver the liquid to the centre of the eddies or vortices formed by the rotation of the rotor E where there exists a zone of' low pressure approximately correspondingin the drawing with the point A.

so The interior of the casing B under working'conditions containsliquid ata higher'V pressure than exists inthe zoneA. A portion of the li uid is normally allowed to pass into the ann arspace B1 between the casing B and rotor E and thence as indicated by the arrows through the passages b2, b3, b* 'andjb to the'annularspace b from whence it passes to the interior of a non-rotating guard or cover'l surroundin the boss ofthe clutch w casin The ar .J collects the heated -liqui and disc arges it into a sump J1 from,

in the casing B by which air may be allowed toescape from the interior-or into which testing instruments may be screwed.

In some cases, it may be desirable that the transmission of power from the driving to the driven element may be rapidly interrupted. To enable this to be done, the casing is provided with quick acting outlet valves K which normally remain closed but can be mechanically or otherwise opened suddenly thereby putting the zone of high pressure in the casing B into communication with the exterior and allowing the liquid in the clutch casing to escape rapidly. y

In the form of valve K shown in Fig. 2 a ring of ports k communicate with the annular space B1 between the rotor E and the casing B where the pressure of the liquid is high. These ports are normally covered by the cylindrical slide k1 (they are shown uncovered in the drawing). The slide k1 is mounted on a spring controlled rod k the end of which is engaged by a projection l on the end of the lever L fulcrumed at l1 on the casing B. The other end of each lever L is connected to a sliding ring M operated by a fork or other device so that by moving this ring M outward from the casing, the slide lc1 is moved inwards against the action of the spring into theposition shown in Fig. 2 to uncover the ports k so that the zone of high pressure B1 is immediately ut into communication with the exterior an allows the liquid inthe clutch casing to escape rapidly.

What I claim as my invention and desire to protect by Letters Patent is:'

1. A hydraulic clutch of the type referred to comprising the combination with a rotor of a casing adapted to rotate, cups in the rotor, and co-acting cups in the casing, in

-both of which cu. s the liquid circulates,

vanes separating t c adjacent cups of the rotor, vanes separatin the adjacent cups of the casin passages rmed in these vanes ,through which fresh cooled 1i 4uid enters and is conveyed to the centres of t e cups where the pressure is at a minimum owing to the vortices set up therein, outlet p near the periphery of the casing through which the heated liquid escapes and a quick actin outlet valve which normally remains cl but which can be suddenly opened to put the zone of high pressure in the basing into communication with the exterior and allow the liquid in the clutch casing to escape rapidly.

2. A hydraulic clutch of the type referredv to comprising the combination with a rotor of a casing adapted to rotate, cups in the rotor and co-acting cups in the in both 7of which cups the liquid circulates, vanes separating the adjacent cups of the rotor, vanes separatin the adjacent cups of the casing,'passages ormed in' these vanes through which fresh cooled liquid enters and is conveyed to the centres of the cups where the pressure is at a minimum owing to the vortlces set up therein, outlet passa es near the periphery of the casing throug which the heated liquid escapes, 'a quick acting outlet valve which normally remains closed but which can be suddenly opened to put the zone of high pressure in the casing into communication with the exterior and allow the liquid in the clutch casing to escape rapidly, and a sump to receive the heated liquid.

In testimony'whereof I have hereuntoset my hand this 18th day of December, 1928. GEORGE HENRY WALKER. 

